This invention relates to an indexing motion machine and method for producing discrete packages of articles, such as vacuum packaged food products or the like.
To produce discrete individual packages of food products such as frankfurters, sliced luncheon meat, cheese or the like, it has been known to employ packaging machines providing either continuous motion or indexing motion. Continuous motion machines typically provide a higher rate of package production than indexing machines. However, indexing machines have been in existence for a long time, and their design is well refined. Accordingly, indexing machines are reliable in operation.
The present invention has as its object to provide an indexing motion package forming machine which is capable of producing packages at a rate equivalent to or greater than the rate at which packages can be produced on a continuous type machine. A further object of the invention is to provide an indexing motion package forming machine utilizing motors with programmable controls to control the movement of the various components of the package forming machine, to provide accurate positioning of the machine components and to provide variability in the package dimensions to accommodate packaging of different products.
In accordance with one aspect of the invention, a packaging machine includes a forming station in which a flexible web of packaging material is deformed so as to provide a cavity adapted to receive the product to be packaged. Forming tooling defines the forming cavity, and the tooling is movable between a first position in which it engages the web of packaging material and acts on the web to form the web into the forming cavity, and a second position in which the tooling is moved away from web. The forming tooling is moved between its first and second positions by a motor having a rotatable output shaft and including a programmable controller associated therewith. A lifting and lowering system is interposed between the forming tooling and the motor output shaft for moving the forming tooling between its first and second positions in response to rotation of the motor output shaft. In a preferred embodiment, the lifting and lowering system includes a cam-type arrangement in which structure defining a cam slot is mounted to the forming tooling, and an arm is mounted to and rotatable with a rotatable member which is driven through a timing belt or the like in response to rotation of the motor output shaft. A roller member is mounted to the arm and is engaged within the cam slot, and alternating clockwise/counterclockwise rotation of the rotatable member causes back and forth movement of the roller within the cam slot to lift and lower the forming tooling.
This aspect of the invention further contemplates a method of forming a product cavity in a flexible web of packaging material, substantially in accordance with the foregoing summary.
In accordance with another aspect of the invention, a packaging machine includes an indexing mechanism for supplying a flexible web of packaging material to the forming station of the packaging machine. A movable advancement mechanism is provided for gripping the flexible web, and preferably comprises a pair of spaced chains. Each chain is preferably provided with a series of gripper members along its length, which grip the edges of the web. A motor having a rotatable output shaft and having a programmable controller associated therewith, is drivingly engaged with the pair of chains. Intermittent operation of the motor provides indexing advancement of the web to the forming station. The forming station includes forming tooling for deforming the flexible web to form a cavity adapted to receive product to be packaged.
The invention further contemplates a method of indexingly advancing a web of packaging material in a packaging apparatus, substantially in accordance with the foregoing summary.
In accordance with yet another aspect of the invention, a packaging machine includes a forming station in which a flexible web of packaging material is supplied to the forming station. A forming box is located at the forming station and includes an internal forming cavity. The forming box is movable to a forming position in which the web is located over the forming cavity. A vacuum mechanism provides negative air pressure to the forming cavity of the forming box when the forming box is in its forming position. A plug assist mechanism assists the web to conform to the contour of the forming cavity when the forming box is in its forming position. The plug assist mechanism comprises a plug member reciprocably movable between an operative position in which it engages the web and moves the web within the cavity to assist the web to conform to the cavity, and an inoperative position in which the plug member is withdrawn from the cavity. A motor having a rotatable output shaft and a programmable controller associated therewith is provided for reciprocably moving the plug member between its operative and inoperative positions in response to operation of the motor. In a preferred embodiment, the plug member is mounted to a frame assembly, and the plug member is reciprocably movable between its operative and inoperative positions by lowering and raising the frame assembly in response to rotation of the motor output shaft, for moving the plug member between its operative and inoperative positions. In a particularly preferred embodiment, the frame assembly is lowered and raised by means of a linear actuator connected between the motor output shaft and the frame assembly for lowering and raising the frame assembly in response to alternating clockwise/counterclockwise rotation of the motor output shaft.
This aspect of the invention further contemplates a method of assisting a flexible web of packaging material to conform to a forming cavity, substantially in accordance with the foregoing summary.
In accordance with yet another aspect of the invention, a packaging machine and method incorporates forming tooling, an indexing web drive, and a plug assist mechanism, each of which is independently driven by one or more motors having programmable controllers, so as to allow each component to be independently programmed and controlled. This provides variability in the type of package which can be formed by the machine, as well as providing accurate control and adjustment of the various packaging components.
In each of the above-noted aspects of the invention, the motor preferably comprises a programmable servo motor.
Various other features, objects and advantages of the invention will become apparent from consideration of the following description taken together with the drawings.